77
PRO-
EN
Green LED
Off: Unit Stopped
Flashing: Unit is starting
Fixed: Unit is working.
Red LED
Off: No alarm
Flashing: Warning
Fixed: Unit in fault
UP/DOWN keys
Enter key
ON/OFF key
Go back to previous
page key
Knob to control
the contrast
Hardware
The control system consists of a board called NRCP2-BASE for
a unit with up to two compressors.
The units with heat pumps, equipped with elec-
tric heating element, have an additional board called
PD-AUX
NRCP2-BASE
board
manages
the
information
flow
from the various pressure and temperature probes.
The user interface includes an alphanumeric display with 8
lines, two LEDs, five navigation keys and a knob to control the
contrast.
Power supply
All boards are powered by a 24V alternating current. In case
of power blackout, the unit will automatically restart without
the need of an external command.
Respect
connection
correct
polarity
to
avoid
damages to the control boards.
LED signals on the electronic boards
All electronic boards inside the unit constantly check the cor-
rect operation of their electronic circuits. Each one of them
includes a LED indicating board operation status.
Signalling could be as follows:
• Flashing red LED (ON with a frequency of two seconds):
indicates board correct operation.
• Flashing red LED (ON with a frequency other than two seconds):
indicates a board malfunctioning.
• Flashing green LED on all boards: boards are communicating
correctly through the internal bus.
• Steady green LED: boards have a bus wiring problem.
• Flashing
orange
LED
(on
Master
board
only):
It indicates that the board is communicating through the
CCN bus.
Sensors
Measurement devices inside the unit - also called sensors -
are:
• Pressure
sensors:
there
are
two
electronic
sensors positioned in the high and low pressure lines o f
the cooling circuit.
• Temperature sensors: there are two sensors positioned
upstream and downstream the plate exchanger.
• Outside temperature sensor: fitted on the unit,
under a metal plate.
• Temperature sensor (for cascading machines –
optional): used only in case of a cascading connection
of
two
units
and
controls
system
water
temperature.
• Temperature sensor to measure the evaporation
temperature in the exchanger block.
